Working on the spinoff of a multibillion-dollar operation while also handling an acquisition valued at about $3.5 billion has made 2011 a busy year for Sylvia Kerrigan.

“My brain has been in overdrive for so long, I wake up in the middle of the night and think of four things I have to do,” says Kerrigan, who has been vice president, general counsel and secretary of Houston-based Marathon Oil Co. since 2009. “But for a recently minted GC, what a great set of experiences.”